But when it comes to momentum, the Sanders camp says it's on a roll and they won't stop until the Democratic National Convention in July.

On Wednesday, the Vermont senator urged his supporters the primaries were far from over. "If we do really well in the next eight contests, we can end up with more pledged delegates than Secretary Clinton," he said at a Billings, Montana, rally.

But is that statement actually true? It depends how you define "really well." CNN's Chief National Correspondent John King crunched the numbers and Sanders would need 67% of the remaining pledged delegates -- not counting superdelegates -- to beat Clinton by one pledged delegate. But that number doesn't get him to the 2,383 delegates needed to clinch the Democratic nomination. Counting superdelegates, Sanders is mathematically blocked from capturing the Democratic nomination on the first ballot in July unless some of the superdelegates switch allegiance from Clinton to Sanders.

So it's possible for Sanders to win, but if the past primaries of this cycle tell us anything, it's not probable.

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That doesn't even factor in superdelegates. Clinton has 516 superdelegates pledged to her, compared to Sanders' 41, so even if he finished strong, if all the superdelegates stayed with Clinton, those would put her over the 2,383 threshold needed to win the Democratic nomination.